/*
 * Copyright (c) 2005, Swedish Institute of Computer Science
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * This file is part of the uIP TCP/IP stack
 *
 * @(#)$Id: dhcpc.c,v 1.2 2006/06/11 21:46:37 adam Exp $
 */

#include <stdio.h>
#include <string.h>

#include "uip.h"
#include "dhcpc.h"
#include "timer.h"
#include "pt.h"

#define STATE_INITIAL         0
#define STATE_SENDING         1
#define STATE_OFFER_RECEIVED  2
#define STATE_CONFIG_RECEIVED 3

static struct dhcpc_state s;

struct dhcp_msg {
	u8_t op, htype, hlen, hops;
	u8_t xid[4];
	u16_t secs, flags;
	u8_t ciaddr[4];
	u8_t yiaddr[4];
	u8_t siaddr[4];
	u8_t giaddr[4];
	u8_t chaddr[16];
#ifndef UIP_CONF_DHCP_LIGHT
	u8_t sname[64];
	u8_t file[128];
#endif
	u8_t options[312];
};

#define BOOTP_BROADCAST 0x8000

#define DHCP_REQUEST        1
#define DHCP_REPLY          2
#define DHCP_HTYPE_ETHERNET 1
#define DHCP_HLEN_ETHERNET  6
#define DHCP_MSG_LEN      236

#define DHCPC_SERVER_PORT  67
#define DHCPC_CLIENT_PORT  68

#define DHCPDISCOVER  1
#define DHCPOFFER     2
#define DHCPREQUEST   3
#define DHCPDECLINE   4
#define DHCPACK       5
#define DHCPNAK       6
#define DHCPRELEASE   7

#define DHCP_OPTION_SUBNET_MASK   1
#define DHCP_OPTION_ROUTER        3
#define DHCP_OPTION_DNS_SERVER    6
#define DHCP_OPTION_REQ_IPADDR   50
#define DHCP_OPTION_LEASE_TIME   51
#define DHCP_OPTION_MSG_TYPE     53
#define DHCP_OPTION_SERVER_ID    54
#define DHCP_OPTION_REQ_LIST     55
#define DHCP_OPTION_END         255

static const u8_t xid[4] = {0xad, 0xde, 0x12, 0x23};
static const u8_t magic_cookie[4] = {99, 130, 83, 99};
/*---------------------------------------------------------------------------*/
static u8_t*
add_msg_type(u8_t* optptr, u8_t type)
{
	*optptr++ = DHCP_OPTION_MSG_TYPE;
	*optptr++ = 1;
	*optptr++ = type;
	return optptr;
}
/*---------------------------------------------------------------------------*/
static u8_t*
add_server_id(u8_t* optptr)
{
	*optptr++ = DHCP_OPTION_SERVER_ID;
	*optptr++ = 4;
	memcpy(optptr, s.serverid, 4);
	return optptr + 4;
}
/*---------------------------------------------------------------------------*/
static u8_t*
add_req_ipaddr(u8_t* optptr)
{
	*optptr++ = DHCP_OPTION_REQ_IPADDR;
	*optptr++ = 4;
	memcpy(optptr, s.ipaddr, 4);
	return optptr + 4;
}
/*---------------------------------------------------------------------------*/
static u8_t*
add_req_options(u8_t* optptr)
{
	*optptr++ = DHCP_OPTION_REQ_LIST;
	*optptr++ = 3;
	*optptr++ = DHCP_OPTION_SUBNET_MASK;
	*optptr++ = DHCP_OPTION_ROUTER;
	*optptr++ = DHCP_OPTION_DNS_SERVER;
	return optptr;
}
/*---------------------------------------------------------------------------*/
static u8_t*
add_end(u8_t* optptr)
{
	*optptr++ = DHCP_OPTION_END;
	return optptr;
}
/*---------------------------------------------------------------------------*/
static void
create_msg(register struct dhcp_msg* m)
{
	m->op = DHCP_REQUEST;
	m->htype = DHCP_HTYPE_ETHERNET;
	m->hlen = s.mac_len;
	m->hops = 0;
	memcpy(m->xid, xid, sizeof(m->xid));
	m->secs = 0;
	m->flags = HTONS(BOOTP_BROADCAST); /*  Broadcast bit. */
	/*  uip_ipaddr_copy(m->ciaddr, uip_hostaddr);*/
	memcpy(m->ciaddr, uip_hostaddr, sizeof(m->ciaddr));
	memset(m->yiaddr, 0, sizeof(m->yiaddr));
	memset(m->siaddr, 0, sizeof(m->siaddr));
	memset(m->giaddr, 0, sizeof(m->giaddr));
	memcpy(m->chaddr, s.mac_addr, s.mac_len);
	memset(&m->chaddr[s.mac_len], 0, sizeof(m->chaddr) - s.mac_len);
#ifndef UIP_CONF_DHCP_LIGHT
	memset(m->sname, 0, sizeof(m->sname));
	memset(m->file, 0, sizeof(m->file));
#endif

	memcpy(m->options, magic_cookie, sizeof(magic_cookie));
}
/*---------------------------------------------------------------------------*/
static void
send_discover(void)
{
	u8_t* end;
	struct dhcp_msg* m = (struct dhcp_msg*)uip_appdata;

	create_msg(m);

	end = add_msg_type(&m->options[4], DHCPDISCOVER);
	end = add_req_options(end);
	end = add_end(end);

	uip_send(uip_appdata, end - (u8_t*)uip_appdata);
}
/*---------------------------------------------------------------------------*/
static void
send_request(void)
{
	u8_t* end;
	struct dhcp_msg* m = (struct dhcp_msg*)uip_appdata;

	create_msg(m);

	end = add_msg_type(&m->options[4], DHCPREQUEST);
	end = add_server_id(end);
	end = add_req_ipaddr(end);
	end = add_end(end);

	uip_send(uip_appdata, end - (u8_t*)uip_appdata);
}
/*---------------------------------------------------------------------------*/
static u8_t
parse_options(u8_t* optptr, int len)
{
	u8_t* end = optptr + len;
	u8_t type = 0;

	while(optptr < end) {
		switch(*optptr) {
			case DHCP_OPTION_SUBNET_MASK:
				memcpy(s.netmask, optptr + 2, 4);
				break;

			case DHCP_OPTION_ROUTER:
				memcpy(s.default_router, optptr + 2, 4);
				break;

			case DHCP_OPTION_DNS_SERVER:
				memcpy(s.dnsaddr, optptr + 2, 4);
				break;

			case DHCP_OPTION_MSG_TYPE:
				type = *(optptr + 2);
				break;

			case DHCP_OPTION_SERVER_ID:
				memcpy(s.serverid, optptr + 2, 4);
				break;

			case DHCP_OPTION_LEASE_TIME:
				memcpy(s.lease_time, optptr + 2, 4);
				break;

			case DHCP_OPTION_END:
				return type;
		}

		optptr += optptr[1] + 2;
	}

	return type;
}
/*---------------------------------------------------------------------------*/
static u8_t
parse_msg(void)
{
	struct dhcp_msg* m = (struct dhcp_msg*)uip_appdata;

	if(m->op == DHCP_REPLY &&
	        memcmp(m->xid, xid, sizeof(xid)) == 0 &&
	        memcmp(m->chaddr, s.mac_addr, s.mac_len) == 0) {
		memcpy(s.ipaddr, m->yiaddr, 4);
		return parse_options(&m->options[4], uip_datalen());
	}

	return 0;
}
/*---------------------------------------------------------------------------*/
static
PT_THREAD(handle_dhcp(void))
{
	PT_BEGIN(&s.pt);

	/* try_again:*/
	s.state = STATE_SENDING;
	s.ticks = CLOCK_SECOND;

	do {
		send_discover();
		timer_set(&s.timer, s.ticks);
		PT_WAIT_UNTIL(&s.pt, uip_newdata() || timer_expired(&s.timer));

		if(uip_newdata() && parse_msg() == DHCPOFFER) {
			s.state = STATE_OFFER_RECEIVED;
			break;
		}

		if(s.ticks < CLOCK_SECOND * 60) {
			s.ticks *= 2;
		}
	} while(s.state != STATE_OFFER_RECEIVED);

	s.ticks = CLOCK_SECOND;

	do {
		send_request();
		timer_set(&s.timer, s.ticks);
		PT_WAIT_UNTIL(&s.pt, uip_newdata() || timer_expired(&s.timer));

		if(uip_newdata() && parse_msg() == DHCPACK) {
			s.state = STATE_CONFIG_RECEIVED;
			break;
		}

		if(s.ticks <= CLOCK_SECOND * 10) {
			s.ticks += CLOCK_SECOND;
		} else {
			PT_RESTART(&s.pt);
		}
	} while(s.state != STATE_CONFIG_RECEIVED);

#if 0
	printf("Got IP address %d.%d.%d.%d\n",
	       uip_ipaddr1(s.ipaddr), uip_ipaddr2(s.ipaddr),
	       uip_ipaddr3(s.ipaddr), uip_ipaddr4(s.ipaddr));
	printf("Got netmask %d.%d.%d.%d\n",
	       uip_ipaddr1(s.netmask), uip_ipaddr2(s.netmask),
	       uip_ipaddr3(s.netmask), uip_ipaddr4(s.netmask));
	printf("Got DNS server %d.%d.%d.%d\n",
	       uip_ipaddr1(s.dnsaddr), uip_ipaddr2(s.dnsaddr),
	       uip_ipaddr3(s.dnsaddr), uip_ipaddr4(s.dnsaddr));
	printf("Got default router %d.%d.%d.%d\n",
	       uip_ipaddr1(s.default_router), uip_ipaddr2(s.default_router),
	       uip_ipaddr3(s.default_router), uip_ipaddr4(s.default_router));
	printf("Lease expires in %ld seconds\n",
	       ntohs(s.lease_time[0]) * 65536ul + ntohs(s.lease_time[1]));
#endif

	dhcpc_configured(&s);

	/*  timer_stop(&s.timer);*/

	/*
	 * PT_END restarts the thread so we do this instead. Eventually we
	 * should reacquire expired leases here.
	 */
	while(1) {
		PT_YIELD(&s.pt);
	}

	PT_END(&s.pt);
}
/*---------------------------------------------------------------------------*/
void
dhcpc_init(const void* mac_addr, int mac_len)
{
	uip_ipaddr_t addr;

	s.mac_addr = mac_addr;
	s.mac_len  = mac_len;

	s.state = STATE_INITIAL;
	uip_ipaddr(addr, 255, 255, 255, 255);
	s.conn = uip_udp_new(&addr, HTONS(DHCPC_SERVER_PORT));

	if(s.conn != NULL) {
		uip_udp_bind(s.conn, HTONS(DHCPC_CLIENT_PORT));
	}

	PT_INIT(&s.pt);
}
/*---------------------------------------------------------------------------*/
void
dhcpc_appcall(void)
{
	handle_dhcp();
}
/*---------------------------------------------------------------------------*/
void
dhcpc_request(void)
{
	u16_t ipaddr[2];

	if(s.state == STATE_INITIAL) {
		uip_ipaddr(ipaddr, 0, 0, 0, 0);
		uip_sethostaddr(ipaddr);
		/*    handle_dhcp(PROCESS_EVENT_NONE, NULL);*/
	}
}
/*---------------------------------------------------------------------------*/
